Knowledge and Understanding
by KagamineToxins
Summary: It is the study of chemistry, in which Yuuko will come to understand a few other things along the way . . .
1. Study

**Doesn't own BakaTest.**

** I can't see Yuuko failing chemistry, but I hate science, so I wrote this anyway. Never failed, but the terms in here are still simplistic, due to lack of interest . . . I also apologize in advance for any lame jokes you don't understand, and the cooking thing? I actually had a teacher in real life assign that for extra credit.**

** Not surprisingly, it's twincest. I don't get it either, but I seem to write a lot of these . . .**

** I was also informed that Hideyoshi doesn't refer to Yuuko by name, so I'll be writing my stories accordingly from now on. Thank you, reviewer!**

**Introduction to Chemistry**

"We're perfect together!" one giggling, hyperactive gossiper said to the other.

"Oh, so there's some really good chemistry between you, then?"

They were hysterically giddy, heartily applauding one another over trivial things like boyfriends at the instant Yuuko Kinoshita was walking past. They were too damn loud; even if she tried blocking them out, she would still be able to hear them. And when they spoke, it was with long, drawn out words shoved in hastily between snaps of gum. They were obviously not the intelligent type, Yuuko thought snobbishly. How was it they were enrolled here? And not in Class F with the rest of the school's failures?

'Chemistry is not a proper term for romance,' Yuuko thought to herself. She was a collection of romances herself – if her collection of boys' love novels weren't any indicator – but she also preferred to keep things in realistic terms. Or at least within the boundaries of fanservice. 'Chemistry is the mixing of multiple particles and atoms to create something new, or to cause a particular effect. You can't mix two humans together!'

Later, and in a rather pleasant mood, she decided to recall this story to Hideyoshi. He didn't find it quite as funny. In fact, he almost looked disappointed in her – the last thing Yuuko would have expected, and she didn't even understand why. So she demanded to know.

Hideyoshi let out a sigh and slowly shook his head. "You just don't get it."

**Taking Notes**

It didn't turn out to be a subject Yuuko liked much. Maybe some of the other Class A students were naturally born geniuses, textbook in hand, but she occasionally had to work for her grades. 'And the sciences,' she thought stiffly, 'are far more work than they are worth.'

There was something about the subject that she just couldn't wrap her mind around, or perhaps it was a problem with the way it was being taught. Regardless, in these instances, she always found her mind wandering, emptying the same dreamy, absent state she so often caught Hideyoshi in. She didn't like to think this was a fault of her own, so perhaps it was hereditary instead.

When the teacher said, "Find the molar mass . . ." Yuuko was not enthusiastically scribbling notes and numbers into her notebook as the other students were. She'd been lost at the word 'molar'.

Molars, like the ones in the back of your mouth. Hideyoshi had cried horribly the first time he lost a baby molar. For some reason, it hadn't occurred to him that those would eventually be replaced with adult teeth also, just like the ones in front. Although Yuuko had berated him for this, it was a product of embarrassment on her part. She hadn't thought of this herself, and she'd come very close to being the one in this position instead.

The main scene had concluded after much sobbing and some screaming, parents rushing around hectically and Yuuko yelling at her twin for being a baby about a little bit of blood and pain. But she'd also been more supportive, in her own way. After their parents finally disappeared, Yuuko fetched him an ice cube, a peppermint, and a kiss on the cheek.

She'd explained it to him as this: ice to ease the pain, candy for soothing, and a kiss to make it better, because she sometimes doubted their parents' insistence that a kiss had that kind of healing power on its own. It was innocent at the time, but thinking about it now made her face flush with embarrassment.

Something sharp poked her in the back, pulling her out of this reverie. Before she could turn around to scowl at the offender – Kubo, with a pencil in hand – the teacher called her name. Quite impatiently, as if it he'd done so many times already.

"You zoned out," Kubo whispered helpfully. And also very obviously, giving Yuuko yet another thing to grimace at.

"I-I'm sorry," she replied quickly, as the teacher prompted her again. Her mind scrambled to come up with an excuse. "I-I just . . ."

"She must not be feeling well," someone else offered helpfully. Yuuko silently thanked her savior.

"T-that's it. I'm really sorry . . ."

The teacher examined her a bit more closely now. "Do you want to go to the nurse's office?" he asked finally. "You do look a bit flushed . . ."

She nodded quickly. Cutting class was a very Hideyoshi thing to do, but for this one day, it might just pay off . . .

**Homework**

Explaining diatomic molecules to Hideyoshi was harder than she had imagined it to be. What kind of education did those kids in Class F receive anyway? It was no wonder that they failed every year!

"Wait, wait! I think I'm starting to get it."

"Okay. So . . . ?" Yuuko waited for him to continue – it wasn't that difficult to understand, and she was getting a bit impatient with him.

His finger fell to a random square on the periodic table of elements. "So if we take this one, Fe, and have only one of it . . ." his eyebrows furrowed. "We get . . ."

"Moron," Yuuko offered. Her brother looked rather abashed at this, so she continued, rather bored, "Fe is iron. One is mono. And, for the record, iron is a stable element. It doesn't need to be changed."

The students of Class F may not have been smart, but their mistakes were definitely funny. Hideyoshi still looked confused though, and there was a slight silence between them before he asked, "Wouldn't that make it 'monoron'?" which kind of took the funny out of Yuuko's joke.

"Shut up!"

**Extra Credit**

Yuuko stepped in front of the television angrily, glaring with her hands on her hips. "Extra credit," she barked. "You said you'd help me. Do it. Now!"

"But I can't-"

"No complaining!" Yuuko interrupted, dropping to the floor and slamming the off button on the game console. Above Hideyoshi's whining and protests, she continued, "If I have to suffer, so do you!"

It was the nicest method she knew of to coerce him into keeping her company. But since he still wasn't moving, she did it for him. Stepping behind her twin, she looped her arms around his chest and forcefully dragged him into the kitchen as he thrashed and protested. Bitterly, Yuuko mused that it was his own fault for not coming on his own the first time she asked. Or the second. And this happened frequently at the Kinoshita household, since Hideyoshi never seemed to learn that there were other, far less painful ways, to do things.

In the kitchen, Hideyoshi continued complaining that he did not see the point of having to make a cake in order to pass a science class. Frankly, neither did Yuuko, but she lied about it anyway. "It's an exercise in following instructions and combining ingredients in small amounts," she recited, thinking back on what the teacher had told the class.

"And I still don't see how this is my problem," he mumbled, which Yuuko happened to overhear, earning him a merciless smack.

"Just stay here and help me." Because I wanted to spend some time with you. "It will go faster this way, and then you can get back to your stupid game."

Hideyoshi almost started protesting again – it was a 'stupid game' that Yuuko happened to play all of the time – but stopped himself. His sister was already beyond caring, busying herself with digging through the supply cabinet – that dark, cramped space their parents kept all the cooking ingredients in case they ever decided they wanted to make something themselves for a change. She came back with almost more than she could carry, and definitely more than what Hideyoshi thought was necessary to make a simple cake.

"I think your chemistry teacher just wants free dessert," he muttered dryly, as Yuuko was already organizing things on the counter, and giving him orders.

Upon hearing this, she paused momentarily, holding an egg over the rim of a large blue bowl. For a moment, the other twin was almost afraid that he had offended her in some way. But then she carried on nonchalantly, and even agreed with him. "Yeah, you're probably right."

There was another pause, long enough to make Hideyoshi think they were dropping conversation entirely. But then Yuuko spoke up again, with something completely unexpected.

"Go get the hot sauce," she said, which left him in a momentary state of confusion.

"Eh! Sister, what for?"

Of course, he already knew the answer, or at least had a good guess.

Yuuko smiled back at him, a tad too cheerily for comfort. "And when he chokes on it, I'll just smile sweetly and say 'Sorry, sensei! I must be a really bad cook!'"

"Haha," Hideyoshi laughed nervously. It was kind of cute. "That was really funny, sister!"

"I know," she agreed, surprising her brother yet again. He may not have wanted to believe she was being serious, but he'd certainly not expected her to actually be joking. "That was a good one, don't you think? It's to make up for that bad one earlier, with the girls talking about their boyfriends."

Her brother laughed again, the unease slipping away now. His initial assumption had been dead on – Yuuko really had been serious – but she decided she liked Hideyoshi's normal laugh better than the nervous one. Poisoning her chemistry teacher wasn't the right way to gain Hideyoshi's positive attentions; he was far too gentle to tolerate something like that.

So she'd just have to do it some other time.

For now, it was much more pleasant hearing his happiness – a laugh that matched his kindly demeanor perfectly – than it was listening to the sound of a gagging old man.

**It's not complete, but I'm breaking it up into two segments. It's your own fault. You guys wanted a longer story, so you got one, haha!**

**Oh, but I don't actually have the second half drafted yet. Haven't even started, so I just hope it actually happens . . . (face/palm). But uploading both halves at once would have made it a much too long read for a simple fanfiction. I come on this site for quick reads, don't you?**


	2. Failure

**Consider this your Christmas gift. In return, I want someone other than me to write one of these stories. HideYuu, please. Or just Yuuko, since she's my favorite character in the show.**

**Althea****: I had a story like that in mind anyway. So it might happen. But this stuff is easier to discuss through PM, okay?**

**Pop Quiz**

It happens to the best of people. Failure. But Yuuko was supposed to be the best of the best; she was at the top of class A, even. The results of the quiz were dismaying. She opted to tuck it away neatly in her folder, away from anyone who might see it, and definitely far away from the eyes of her parents.

There were dozens of excuses she could have used to justify her failure: it was a pop quiz, she hadn't been feeling her best today, it was too early in the morning . . . but Yuuko liked to be realistic. She hadn't been studying enough, so tonight she would have to make up for the lack of previous effort.

**Late Night Studying**

Studying these days required a lot more caffeine than Yuuko remembered.

There's a knock on her door, despite the sign asking for no interruptions. The voice of her brother calls to her, asking if she was okay. And when she replied, 'fine', he waltzed in as if that were an invitation.

It's slightly infuriating. She could easily blame her twin for this; Hideyoshi has been taking up a lot of her time lately, and the most he has to offer for it is the fresh mug of coffee he places on her desk. His has brushes past hers as he does so, resulting in a powerful surge of emotion that Yuuko can't recognize. The whole situation is frustrating, and, at the same time, she doesn't really mind when she sees the gentle worry in his eyes.

Yuuko decides it's best to just blame it on the textbook.

"I happened to notice the light in your room was still on," Hideyoshi begins awkwardly.

He isn't used to stepping into his sister's room at such a late hour in the night. It's around midnight, and she still hasn't showered. She hasn't moved from this place since dinner, and it's evident by how irritated she looks. Yuuko's hair is tousled, more so than usual, as if she's been pulling it out in irritation. Hideyoshi himself can't stand more than fifteen minutes of reading at a time, so he wonders if this is how his sister manages to endure it.

"Can't read in the dark," Yuuko replied sharply.

Hideyoshi doesn't seem at all taken aback. He just nods patiently, and continues, "I brought you more coffee, but that doesn't mean you need it." There is a slight pause, because he's not used to being the one to give orders. In the end, he doesn't phrase it as such, but merely as a kind suggestion. "I think you ought to go to bed soon. Staying up this late can't be good for you."

"Soon," she says. But she waves him away as if she weren't really listening.

Several hours later, she glances at the digital clock on her desk. The numbers glow too brightly, glaring red as if they're angry at her. It's past three in the morning, which would explain why the tiny words in her textbook have become so blurred and incomprehensible that she doesn't even recognize them anymore. They all meld together as if they were one giant blob.

But does Yuuko feel like she accomplished anything? She climbs into bed with not a single thought focused on chemistry, but she does realize that her pillow makes a comfortable substitute for Hideyoshi, and her mind is too tired to comprehend how this might be wrong.

**Correcting Homework**

Yuuko's attention had been failing more frequently during classes, especially in her least favorite subject. She would sit, twirling the pencil in her hand, staring straight ahead at the board in front of the room, without actually seeing it. The voice ringing in her head was not the teacher's, droning on about homework corrections, but Hideyoshi's, babbling incessantly about some game he'd picked up at the bargain store.

He did quite a bit of babbling, though usually more at home, where he was more comfortable. Recently he'd really been starting to open up to her again, but around his friends he kept a calmer facade. But when he was excited, he liked to talk. A lot. But it also made his features shine, and sometimes he even used his talent of voice mimicry to reenact certain scenes and do impressions, which was usually quite hilarious. So Yuuko could say she didn't mind having her ear talked off on these occasions, though Hideyoshi sometimes spoke far too quickly for her to keep up.

Despite his excitement over the game, she'd already been allowed to play it once. It was for a handheld console, and she'd asked lots of questions to encourage him to stick around, because she kind of liked how he hovered over her shoulder. He pointed directions at the screen and guided her through them; his directions came out in warm breaths against her neck.

Yuuko remembered saying to him, "You're really good at this one, aren't you?"

It was a visual novel type game, the setting involved a classroom and a school filled with mysteries. Instead of dourly pointing out that this was the type of game Yuuko should be better at, Hideyoshi seemed to take her compliment pridefully. He didn't even point out how easy it was, just said, "I thought you might like it," and beamed as if he had done something right.

Yuuko couldn't see his face, but she could feel the exuberance radiating, and it made her smile as well.

It was at this point that Yuuko was interrupted from her daydream, as the teacher was clearly starting to lose patience with having to call her name fifteen times before getting a response. "Yuuko!" he snapped, causing the girl to jump and the whole class to stare at her.

"Y-yes, sir?"

Simultaneously, she was thinking of the last scene they'd gone through before pressing the 'save' button Sunday night. A chemistry room. Of course. She'd been a bit annoyed when the characters had been navigated toward it, as if it weren't already haunting her life enough.

This had brought up a question that Yuuko hadn't quite expected, from a scenario that she'd almost managed to forget. Almost nonchalantly, he mentioned the two gossipers from earlier.

"What is a limiting reactant?"

At the same time, her mind was hearing Hideyoshi ask, "Do you understand it yet?"

She wasn't hearing the teacher's question. So, in a daze, she answered truthfully: "I don't know."

**P.S. I had to type this with a cat stepping all over my keyboard. Leona, you are not helping.**

**The game I described them playing isn't based off anything in particular. Also, writing/editing at three in the morning. May result in worse quality than usual.**

**Turns out, there's also going to be a third segment to this story. And that is where it will officially end. For real, this time. Will try to make up for this part with a more interesting conclusion. I have a good idea of how it's going already, but I'm too tired to start writing.**


End file.
